A woman who comes home from the military unannounced to surprise her husband, also in the military, finds him in their bed with someone else and slaps him and throws something at him, is found guilty of domestic violence. She is banned from her own home, (restraining order), her guns are taken away, and her ability to get jobs in the future, seriously compromised.
A man who slightly injures his 16 year old child while dragging her back into the house house at 10 pm at night while she screams that he's trying to kill her for all the neighbors to hear, is charged, even thought the some of the bruises the police found look suspiciously like they were self inflicted. The bruises on her arms where he grabbed her are real. She wanted to go party with her druggie friends and Dad wanted her to go to sleep so she could go to school the next day. Dad get lucky this time, it only costs him tens of thousands of dollars and a few weeks in jail.
A family catches their 17 year old son with drugs, they demand to know where he got them and the boy curses at them. Dad, who is smaller than the son slaps him, so the son marches in his room and uses the cell phone his folks gave him to call the police who arrest his Dad. It's clearly illegal for a Dad to slap his son.
And the most bizarre one I know personally, a rather stupid man who is a real wimp, was angry at his wife for overspending, called a friend and for the hundredth time said things like "I'm going to strangle her". His friend was on speaker phone, a third party overheard and called his wife the next day, and his wife called the police claiming she believed the threat. The next day the police came by and asked him if he'd really uttered those words, he stupidly say yes, believing his meaningless blathering was harmless as long as he never laid a hand on anyone, and they locked him up. He's now a felon, who has never laid a hand on anyone.
I don't like violence but there is a huge difference between beating the crap out of someone, and pushing the around, slapping them, or even attempting to restrain a disobedient child. I don't think a parent should ever go to jail and be convicted of domestic violence for trying to stop a child from leaving the house late at night.